<?php

$data = [
    'jsonrpc' => '2.0',
    'method' => 'backup',
    'params' => [
        'authToken' => 'PUT_YOUR_TOKEN_HERE',
//        'id' => '11',
//        'userPass' => 'debian',
//        'text' => 'Keepass',
//        'categoryId' => '5',
//        'customerId' => '1',
//        'pass' => '1234',
//        'login' => 'root',
//        'url' => 'http://syspass.org',
//        'notes' => 'pruebaaaaaaa'
    ],
    'id' => 1
];

$url = 'http://localhost/api.php';
$content = json_encode($data);

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'POST');
curl_setopt($ch, CURLOPT_POSTFIELDS, $content);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
        'Content-Type: application/json',
        'Content-Length: ' . strlen($content),
        'Accept-Language: de_DE,en-US;q=0.7,en;q=0.3'
    )
);

$result = curl_exec($ch);

$status = curl_getinfo($ch, CURLINFO_HTTP_CODE);

if ($status != 200) {
    die("Error: call to URL $url failed with status $status, response $result, curl_error " . curl_error($ch) . ", curl_errno " . curl_errno($ch));
}

curl_close($ch);

echo '<pre>';
var_dump(json_decode($result));
echo '</pre>';